1. Center for Bio/Molecular Science and Engineering Code 6900, U.S. Naval Research Laboratory, Washington,
District of Columbia 20375, United States
2. College of Science, George Mason University, Fairfax, Virginia22030United States
3. Department of Chemistry, Case Western Reserve University, Cleveland, Ohio44106, United States
4. Jacobs Corporation, Hanover, Maryland21076, United States
5. Optical Sciences Division Code 5600, U.S. Naval Research Laboratory, Washington, District of Columbia 20375, United States